1. Field of the Invention
This invention relates to a mining machine and more particularly to apparatus mounted on the mining machine for collecting pollutant laden air and separating the pollutants from the air at the mine face during the material dislodging operation.
2. Description of the Prior Art
Federal regulations require that designated areas in underground coal mines comply with controls on the levels of airborne respirable dust permitted at the mine face. Consequently, there have been a number of recent developments in dust abatement in underground mining as disclosed in U.S. Pat. Nos. 3,712,678; 3,792,568; 4,076,315; 4,157,204 and 4,200,036. The United States Bureau of Mines has also developed a twin fan scrubber system for continuous miners. This system combines water scrubbing with ventilation and includes a pair of air ducts mounted on the mining machine boom in which pollutant laden air flows into the inlets of the ducts where water sprays direct a spray of water into the air. The mixture of water spray and pollutant laden air is drawn by a motor driven fan past a scrubber panel to a demister section in the duct. The demister section extracts the pollutants in slurry form from the air flow, which is discharged through an outlet free of the pollutants.
U.S. Pat. Nos. 3,792,568 and 4,076,315 disclose air scrubbers on mining machines for separating the pollutants from the air moving through a duct. The air scrubber has a revolving rotor mounted in a rotor passage of a housing. The rotor causes a flow of air to the scrubber in which the pollutants are removed and the resultant clean air is directed toward the mine face. The pollutants may be discharged onto the conveyor which transports the dislodged material rearwardly on the mining machine. U.S. Pat. No. 3,712,687 also discloses a dust collecting device that utilizes centrifugal fans to draw dust entrained air through openings in collecting chambers where wet-type air scrubbers discharge a curtain of water into a duct causing wetting of the pollutants carried by the air flowing through the duct. The pollutants fall downwardly onto the bottom of the duct where they are removed through a discharge outlet onto the conveyor that transports the material from the mine face.
While it has been suggested to separate pollutants from the air by dust collectors, such as air scrubbers or wet dust collectors, mounted on a continuous mining machine to reduce the levels of airborne respirable dust created by the mining operation, the known devices utilize mechanical fans for moving the air through the dust collector. The fans must have a capacity capable of moving the quantity of air desired at a selected flow rate through the dust collector. The use of fans and motors for operating the fans substantially complicates the dust abatement operation by the need to provide electrical service and the related components for operating the fans. Space must be made available on the mining machine to accommodate the dust collector including the motor, fan and associated electrical equipment. The addition of this equipment on the mining machine creates maintenance problems, increases the noise level of an operating mining machine and in the event motor or fan should become inoperative, requires that the mining machine be shut down until the dust collector is restored to operation.
Therefore, there is need for dust collecting apparatus on a mining machine that eliminates the problems associated with the conventional dust collectors having motor driven fans by preferably eliminating the need for electrical service to the dust collector while being operable to efficiently remove the pollutants from the air generated during the mining operation.